Analysis of Carbon Nanofibers and Porous Silicon for Neural Applications

Keywords

Carbon nanofibers, porous silicon, astrocytes

Abstract

Chronic neural implants are usually made from silicon
materials and are subject to scar tissue formation at the
tissue/implant interface, which interferes with their
functionality. Carbon nanofibers are an example of a
material that may improve neural implant interactions
with native cell populations since these nanofibers have
promising cytocompatibility, mechanical, and electrical
properties. Neural implants may achieve better tissue
interactions simply by incorporating carbon nanofibers
into a silicon matrix. The objective of the present in vitro
study was to determine cytocompatibility properties of
carbon nanofibers and porous silicon materials. Carbon
fiber substrates were prepared from carbon fibers with
either nanoscale or micron scale diameters, and both high
and low surface energy fibers were investigated. Porous
silicon was prepared by treatments resulting in mesoscale
pores with nanoscale roughness between pores.
Astrocytes (glial scar tissue-forming cells) were seeded
separately onto the carbon fiber and silicon substrates.
Astrocytes preferentially adhered on the largest diameter
carbon fiber with the lower surface energy and preferred
the silicon sample with the greatest porosity. These results
indicate that nanoscale surface roughness may deter
astrocyte adhesion. Controlling carbon fiber diameter and
silicon porosity may be approaches for increasing implant
contact with neurons and decreasing scar tissue formation.